The table shows measured absorbance values for an aqueous solution of a single…
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
The table shows measured absorbance values for an aqueous solution of a single colored species at three different wavelengths using a 1.00 cm cuvette.
Wavelength (nm) Absorbance
430 0.12
490 0.87
560 0.64
At which wavelength would the determination of an unknown concentration of this species be most sensitive, and why?
(a) 560nm, because its absorbance is moderate and therefore remains comfortably within the linear range of Beer–Lambert law.
(b) 490nm, because the analyte absorbs most strongly there, giving the greatest change in absorbance per unit concentration.
(c) 430nm, because the lower absorbance minimizes detector saturation and yields a larger percent change in transmitted light.
(d) Any of the wavelengths, because absorbance is directly proportional to concentration regardless of wavelength.